It is often desirable to include color artwork and text in documents. Color can make a document more interesting and more informative. In addition, many software applications that prepare documents and artwork provide many mechanisms to specify color and effects using color. These effects may include designating certain objects in the artwork as having varying degrees of transparency such that objects that are overlapped by another transparent object may still be at least partially visible.
Printers typically do not have the ability to natively process transparency, and the ability to define an object as transparent does not exist in most page description languages such as the PostScript® language. As a result, artwork containing transparency has to be converted to equivalent artwork not containing transparency before printing. In current systems, this conversion is typically done by a desktop application used to create the document. As a result, the conversion may take place without any knowledge of the capabilities of the printing device that will ultimately print the document. Thus the desktop application will generally attempt to emulate some of a printer's characteristics. If the document ends up being sent to a printer with differing characteristics, the resulting printed pages may be quite different from what the document creator desired.